Optimized channel estimation field for enhanced directional multi-gigabit network

ABSTRACT

This disclosure describes systems, methods, and devices related to an optimized channel estimation field. A device may determine an enhanced directional multi-gigabit (EDMG) frame to be sent to a first device using a communication link. The device may determine a channel estimation field (CEF) associated with the EDMG frame, wherein the CEF is comprised of one or more orthogonal frequency division multiplexing (OFDM) symbols. The device may cause to send the EDMG frame to the first device.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. Non-provisional applicationSer. No. 15/393,520, filed Dec. 29, 2016, which claims the benefit ofU.S. Provisional Application No. 62/385,717 filed on Sep. 9, 2016, thedisclosures of which is incorporated herein by reference as if set forthin full.

TECHNICAL FIELD

This disclosure generally relates to systems and methods for wirelesscommunications and, more particularly, to an optimized channelestimation field.

BACKGROUND

Wireless devices are becoming widely prevalent and are increasinglyrequesting access to wireless channels. The growing density of wirelessdeployments requires increased network and spectrum availability.Wireless devices may communicate with each other using directionaltransmission techniques, including but not limited to beamformingtechniques. Wireless devices may communicate over a next generation 60GHz (NG60) network, an enhanced directional multi-gigabit (EDMG)network, and/or any other network.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts a network diagram illustrating an example networkenvironment for an optimized channel estimation field system, inaccordance with one or more example embodiments of the presentdisclosure.

FIGS. 2A-2B depict illustrative schematic diagrams for a time domainimpulse response and a frequency domain impulse response, in accordancewith one or more example embodiments of the present disclosure.

FIGS. 3A-3B depict illustrative schematic diagrams associated with anoptimized channel estimation field system, in accordance with one ormore example embodiments of the present disclosure.

FIGS. 4A-4B depict illustrative schematic diagrams associated with anoptimized channel estimation field system, in accordance with one ormore example embodiments of the present disclosure.

FIG. 5A depicts a flow diagram of an illustrative process associatedwith an optimized channel estimation field system, in accordance withone or more example embodiments of the present disclosure.

FIG. 5B depicts a flow diagram of an illustrative process associatedwith an optimized channel estimation field system, in accordance withone or more example embodiments of the present disclosure.

FIG. 6 depicts a functional diagram of an example communication stationthat may be suitable for use as a user device, in accordance with one ormore example embodiments of the present disclosure.

FIG. 7 depicts a block diagram of an example machine upon which any ofone or more techniques (e.g., methods) may be performed, in accordancewith one or more example embodiments of the present disclosure.

DETAILED DESCRIPTION

Example embodiments described herein provide certain systems, methods,and devices for an optimized channel estimation field. The followingdescription and the drawings sufficiently illustrate specificembodiments to enable those skilled in the art to practice them. Otherembodiments may incorporate structural, logical, electrical, process,and other changes. Portions and features of some embodiments may beincluded in, or substituted for, those of other embodiments. Embodimentsset forth in the claims encompass all available equivalents of thoseclaims.

Devices may communicate over a next generation 60 GHz (NG60) network, anenhanced directional multi-gigabit (EDMG) network, and/or any othernetwork. Devices operating in EDMG may be referred to herein as EDMGdevices. This may include user devices, and/or access points (APs) orother devices capable of communicating in accordance with acommunication standard, including but not limited to IEEE 802.11adand/or IEEE 802.11ay.

A typical enhanced directional multi-gigabit (EDMG) A physical layerconvergence protocol (PLCP) data unit (PPDU) frame format may becomposed of a legacy preamble, a legacy header, an EDMG-Header-Acontaining single user multiple-input multiple-output (SU-MIMO)parameters, an EDMG short training field (EDMG-STF), an EDMG channelestimation field (EDMG-CEF), an EDMG-Header-B containing multi-usermultiple-input multiple-output (MU-MIMO) parameters, a payload data partand optional automatic gain control (AGC) and beamforming training unitsappended at the end of the frame. The legacy preamble, the legacyheader, and a new EDMG-Header-A may be transmitted using single-inputsingle-output (SISO) single carrier (SC) physical layer (PHY)modulation. This provides an opportunity for the legacy directionalmulti-gigabit (DMG) devices to decode legacy headers and identify (usinga signaling bit) that the frame contains the EDMG part not compatiblewith its implementation. This realizes a backward compatibilityrequirement. At the same time, EDMG devices can decode the EDMG-Header-Ausing SISO SC PHY modulation and extract the required parameters forMIMO frame reception. The transmission of the rest of the EDMG frame maybe done using MIMO modulation.

A channel estimation technique plays an important role in communicationsystems. Having an accurate channel response is very important forequalization, demodulation, and decoding. Therefore, the accuracy of thechannel estimation is correlated with system performance. Since inwireless systems radio propagations may be influenced by noise,interferences, location, movements, etc., it may be difficult to detectthe variation of channels. Hence, efficiently estimating the wirelesschannels is an important aspect for reliable communication systems. Inorder to remedy these issues, pilots or reference signals that do notinterfere with one another can be used to provide reliable channelestimation.

Example embodiments of the present disclosure relate to systems,methods, and devices for an optimized channel estimation field.

Directional multi-gigabit (DMG) communications may involve one or moredirectional links to communicate at a rate of multiple gigabits persecond, for example, at least 1 gigabit per second, 7 gigabits persecond, or any other rate. An amendment to a DMG operation in a 60 GHzband, e.g., according to an IEEE 802.11ad standard, may be defined, forexample, by an IEEE 802.11ay project.

In some demonstrative embodiments, one or more devices may be configuredto communicate over a next generation 60 GHz (NG60) network, an enhancedDMG (EDMG) network, and/or any other network. For example, the one ormore devices may be configured to communicate over the NG60 or EDMGnetworks.

In one embodiment, an optimized channel estimation field system mayfacilitate a design of CEF for EDMG orthogonal frequency divisionmultiplexing (OFDM) for the physical layer (PHY). The optimized channelestimation field system may cover single-input single-output (SISO) andMIMO single channel transmission.

In one embodiment, an optimized channel estimation field system maydetermine an EDMG CEF to be comprised of two OFDM symbols. In oneoption, the second symbol may be defined as a copy of the first symbolwith a difference in that it is defined in an inverse sign. In anotheroption, the second OFDM symbol may represent an exact copy of the firstOFDM symbol.

In one embodiment, an optimized channel estimation field system maydefine pilot sequences in the frequency domain, rather than time domainGolay sequences defined in the IEEE 802.11ad standard.

In one embodiment, an optimized channel estimation field system mayfacilitate a mutually orthogonal sequence set, instead of using cyclicshift diversity (CSD) as done in legacy devices (e.g., IEEE 802.11n/ac).The orthogonality property of the sequences prevents the coherent signaltransmission of different space-time streams in case of MIMO and avoidsunintentional beamforming.

The above descriptions are for purposes of illustration and are notmeant to be limiting. Numerous other examples, configurations,processes, etc., may exist, some of which are described in greaterdetail below. Example embodiments will now be described with referenceto the accompanying figures.

FIG. 1 is a network diagram illustrating an example network environment,in accordance with one or more example embodiments of the presentdisclosure. Wireless network 100 may include one or more user device(s)120 and one or more access point(s) (AP) 102, which may communicate inaccordance with IEEE 802.11 communication standards, such as the IEEE802.11ad and/or IEEE 802.11ay specifications. The user device(s) 120 maybe referred to as stations (STAs). The user device(s) 120 may be mobiledevices that are non-stationary and do not have fixed locations.Although the AP 102 is shown to be communicating on multiple antennaswith user devices 120, it should be understood that this is only forillustrative purposes and that any user device 120 may also communicateusing multiple antennas with other user devices 120 and/or AP 102.

One or more illustrative user device(s) 120 and/or AP 102 may beoperable by one or more user(s) 110. The user device(s) 120 (e.g., 124,126, or 128) and/or AP 102 may include any suitable processor-drivendevice including, but not limited to, a mobile device or a non-mobile,e.g., a static, device. For example, user device(s) 120 and/or AP 102may include, a user equipment (UE), a station (STA), an access point(AP), a personal computer (PC), a wearable wireless device (e.g.,bracelet, watch, glasses, ring, etc.), a desktop computer, a mobilecomputer, a laptop computer, an Ultrabook™ computer, a notebookcomputer, a tablet computer, a server computer, a handheld computer, ahandheld device, an internet of things (IoT) device, a sensor device, aPDA device, a handheld PDA device, an on-board device, an off-boarddevice, a hybrid device (e.g., combining cellular phone functionalitieswith PDA device functionalities), a consumer device, a vehicular device,a non-vehicular device, a mobile or portable device, a non-mobile ornon-portable device, a mobile phone, a cellular telephone, a PCS device,a PDA device which incorporates a wireless communication device, amobile or portable GPS device, a DVB device, a relatively smallcomputing device, a non-desktop computer, a “carry small live large”(CSLL) device, an ultra mobile device (UMD), an ultra mobile PC (UMPC),a mobile internet device (MID), an “origami” device or computing device,a device that supports dynamically composable computing (DCC), acontext-aware device, a video device, an audio device, an A/V device, aset-top-box (STB), a blu-ray disc (BD) player, a BD recorder, a digitalvideo disc (DVD) player, a high definition (HD) DVD player, a DVDrecorder, a HD DVD recorder, a personal video recorder (PVR), abroadcast HD receiver, a video source, an audio source, a video sink, anaudio sink, a stereo tuner, a broadcast radio receiver, a flat paneldisplay, a personal media player (PMP), a digital video camera (DVC), adigital audio player, a speaker, an audio receiver, an audio amplifier,a gaming device, a data source, a data sink, a digital still camera(DSC), a media player, a smartphone, a television, a music player, orthe like. It is understood that the above is a list of devices. However,other devices, including smart devices such as lamps, climate control,car components, household components, appliances, etc. may also beincluded in this list.

Any of the user device(s) 120 (e.g., user devices 124, 126, 128), and AP102 may be configured to communicate with each other via one or morecommunications networks 130 and/or 135 wirelessly or wired. Any of thecommunications networks 130 and/or 135 may include, but not limited to,any one of a combination of different types of suitable communicationsnetworks such as, for example, broadcasting networks, cable networks,public networks (e.g., the Internet), private networks, wirelessnetworks, cellular networks, or any other suitable private and/or publicnetworks. Further, any of the communications networks 130 and/or 135 mayhave any suitable communication range associated therewith and mayinclude, for example, global networks (e.g., the Internet), metropolitanarea networks (MANs), wide area networks (WANs), local area networks(LANs), or personal area networks (PANs). In addition, any of thecommunications networks 130 and/or 135 may include any type of mediumover which network traffic may be carried including, but not limited to,coaxial cable, twisted-pair wire, optical fiber, a hybrid fiber coaxial(HFC) medium, microwave terrestrial transceivers, radio frequencycommunication mediums, white space communication mediums, ultra-highfrequency communication mediums, satellite communication mediums, or anycombination thereof.

Any of the user device(s) 120 (e.g., user devices 124, 126, 128), and AP102 may include one or more communications antennas. The one or morecommunications antennas may be any suitable type of antennascorresponding to the communications protocols used by the user device(s)120 (e.g., user devices 124, 126 and 128), and AP 102. Some non-limitingexamples of suitable communications antennas include Wi-Fi antennas,Institute of Electrical and Electronics Engineers (IEEE) 802.11 familyof standards compatible antennas, directional antennas, non-directionalantennas, dipole antennas, folded dipole antennas, patch antennas,multiple-input multiple-output (MIMO) antennas, omnidirectionalantennas, quasi-omnidirectional antennas, or the like. The one or morecommunications antennas may be communicatively coupled to a radiocomponent to transmit and/or receive signals, such as communicationssignals to and/or from the user devices 120 and/or AP 102.

Any of the user device(s) 120 (e.g., user devices 124, 126, 128), and AP102 may be configured to perform directional transmission and/ordirectional reception in conjunction with wirelessly communicating in awireless network. Any of the user device(s) 120 (e.g., user devices 124,126, 128), and AP 102 may be configured to perform such directionaltransmission and/or reception using a set of multiple antenna arrays(e.g., DMG antenna arrays or the like). Each of the multiple antennaarrays may be used for transmission and/or reception in a particularrespective direction or range of directions. Any of the user device(s)120 (e.g., user devices 124, 126, 128), and AP 102 may be configured toperform any given directional transmission towards one or more definedtransmit sectors. Any of the user device(s) 120 (e.g., user devices 124,126, 128), and AP 102 may be configured to perform any given directionalreception from one or more defined receive sectors.

MIMO beamforming in a wireless network may be accomplished using RFbeamforming and/or digital beamforming. In some embodiments, inperforming a given MIMO transmission, user devices 120 and/or AP 102 maybe configured to use all or a subset of its one or more communicationsantennas to perform MIMO beamforming.

Any of the user devices 120 (e.g., user devices 124, 126, 128), and AP102 may include any suitable radio and/or transceiver for transmittingand/or receiving radio frequency (RF) signals in the bandwidth and/orchannels corresponding to the communications protocols utilized by anyof the user device(s) 120 and AP 102 to communicate with each other. Theradio components may include hardware and/or software to modulate and/ordemodulate communications signals according to pre-establishedtransmission protocols. The radio components may further have hardwareand/or software instructions to communicate via one or more Wi-Fi and/orWi-Fi direct protocols, as standardized by the Institute of Electricaland Electronics Engineers (IEEE) 802.11 standards. In certain exampleembodiments, the radio component, in cooperation with the communicationsantennas, may be configured to communicate via 2.4 GHz channels (e.g.802.11b, 802.11g, 802.11n, 802.11ax), 5 GHz channels (e.g. 802.11n,802.11ac, 802.11ax), or 60 GHZ channels (e.g. 802.11ad). In someembodiments, non-Wi-Fi protocols may be used for communications betweendevices, such as Bluetooth, dedicated short-range communication (DSRC),Ultra-High Frequency (UHF) (e.g. IEEE 802.11af, IEEE 802.22), white bandfrequency (e.g., white spaces), or other packetized radiocommunications. The radio component may include any known receiver andbaseband suitable for communicating via the communications protocols.The radio component may further include a low noise amplifier (LNA),additional signal amplifiers, an analog-to-digital (A/D) converter, oneor more buffers, and digital baseband.

Some demonstrative embodiments may be used in conjunction with awireless communication network communicating over a frequency band of 60GHz. However, other embodiments may be implemented utilizing any othersuitable wireless communication frequency bands, for example, anextremely high frequency (EHF) band (the millimeter wave (mmWave)frequency band), a frequency band within the frequency band of between20 GHz and 300 GHz, a WLAN frequency band, a WPAN frequency band, afrequency band according to the WGA specification, and the like.

The phrases “directional multi-gigabit (DMG)” and “directional band(DBand)”, as used herein, may relate to a frequency band wherein thechannel starting frequency is above 45 GHz. In one example, DMGcommunications may involve one or more directional links to communicateat a rate of multiple gigabits per second, for example, at least 1gigabit per second, 7 gigabits per second, or any other rate.

In some demonstrative embodiments, the user device(s) 120 and/or the AP102 may be configured to operate in accordance with one or morespecifications, including one or more IEEE 802.11 specifications, (e.g.,an IEEE 802.11ad specification, an IEEE 802.11ay specification, and/orany other specification and/or protocol).

In one embodiment, and with reference to FIG. 1, there is shown ageneral frame format for the EDMG PPDU 140. The preamble 142 of the EDMGPPDU 140 includes, at least in part, a legacy short training field(STF), a legacy channel estimation field (CEF), a legacy header(L-Header), a new EDMG-Header-A, an EDMG-STF, an EDMG-CEF 144, and anEDMG-Header-B. Beside the preamble 142, the EDMG PPDU 140 may include adata part and optional AGC and beamforming training units (TRNs). It isunderstood that the above acronyms may be different and are not to beconstrued as a limitation because other acronyms may be used for thefields included in an EDMG PPDU 140.

The EDMG-CEF 144 may be used for channel estimation and fordifferentiation between the spatial streams and between the SC PHY andthe OFDM PHY.

In one embodiment, an optimized channel estimation system may define astructure for channel estimation for SISO and for MIMO. For SISO, theEDMG-CEF 144 may be composed of two OFDM symbols. For MIMO, the generalstructure of the EDMG-CEF 144 may be composed of two OFDM symbols havinga set of sequences such that different streams have different sequences,and the sequence definition is not obtained by cyclic shift diversity.It is understood that the above descriptions are for purposes ofillustration and are not meant to be limiting.

FIGS. 2A-2B depict illustrative schematic diagrams for a time domainimpulse response and a frequency domain impulse response, in accordancewith one or more example embodiments of the present disclosure.

Referring to FIG. 2A and FIG. 2B, the legacy DMG-CEF field for the OFDMPHY is defined in a time domain and is based on the Golay sequencessimilar to the single carrier (SC) PHY. The original Golay sequences areconvolved with a shaping filter with about 1.5× rate conversions. Thepulse shaping filter impulse response is defined, for example, in theIEEE 802.11ad standard. The pulse shaping filter impulse response mayhave almost flat frequency response for in-band subcarrierscorresponding to the data and pilots (e.g., as seen in graphs 202 and204). The maximum frequency response amplitude deviation for the datasubcarriers may be equal to ˜0.8 dB. This may allow channel estimationfor in-band subcarriers directly in the frequency domain.

FIGS. 3A-3B depict illustrative schematic diagrams associated with anoptimized channel estimation field system, in accordance with one ormore example embodiments of the present disclosure.

In one embodiment, an optimized channel estimation system may define astructure for channel estimation for SISO and for MIMO. For SISO, thechannel estimation may be composed of two OFDM symbols.

The spectrum definition of an OFDM signal is composed of 512subcarriers, where the three middle subcarriers are used by the zero DCsubcarriers. There are 176 subcarriers on the right and 176 subcarrierson the left of the DC subcarriers that are for data transmission and 79zeros on the left and 78 zeros on the right.

In order to define the EDMG channel estimation field for SISOtransmission, two symbols following each other may be defined. The firstsymbol may be defined to have three DC subcarriers in the middle, whichare used to minimize the leakage of the DC subcarriers to the datasubcarriers. Further, zero subcarriers (e.g., 79 zero subcarriers) maybe added on the left side of the 176 data subcarriers located on theleft of the DC subcarriers, and zero subcarriers (e.g., 78 zerosubcarriers) may be added on the right side of the 176 data subcarrierslocated on the right side of the DC subcarriers in order to meet thespectrum mask requirement. The second symbol is defined as a replica ofthe first one with a difference in that it is defined in an inversesign. When these two symbols are transformed to the time domain, 512samples in the time domain may be obtained. A cyclic prefix may be addedin front of each of these two symbols.

Referring to FIG. 3A, there is shown a SISO EDMG-CEF structure for theOFDM PHY in the time domain. The SISO EDMG-CEF field may be comprised oftwo CEF symbols (e.g., symbol 304 and symbol 306). These two CEF symbolsare OFDM symbols. The symbols may follow each other in the time domain.

In one embodiment, an optimized channel estimation field system maydetermine the composition of the two CEF symbols (e.g., symbol 304 andsymbol 306) in the frequency domain. In one option, the symbol 306 mayhave inverted sign polarity of the symbol 304. In another option, thesecond OFDM symbol may represent an exact copy of the first OFDM symbol.

In one embodiment, in a first option, and in contrast to the IEEE802.11ad standard, the pilot sequence is defined in the frequency domainand for the single channel transmission, the sequence may have thefollowing structure:

Symbol 304: {0_(1:79), SigA_(1:176), 0, 0, 0, SigB_(1:176), 0_(1:78)};and

Symbol 306: {0_(1:79), −SigA_(1:176), 0, 0, 0, −SigB_(1:176), 0_(1:78)};

Where SigA and SigB may occupy 336 data and 16 pilot subcarriers; 3 DCand 78+79 guard band subcarriers are zero ones.

SigA and SigB may be sequences that provide a low peak to average powerratio (PAPR) after application of the inverse discrete Fourier transform(IDFT) transformation in the time domain. It should be understood thatthe symbol structure above is defined before a DFT shift operation.After the DFT shift operation is applied, the symbols may be transformedto be:

X_(CB=1)={0, 0, SigB_(1:176), 0_(1:78), 0_(1:79), SigA_(1:176), 0,}. TheEDMG-CEF field represented in the time domain may be defined as follows:

X_(CB=1)=IDFT(X_(CB=1)); where x_(CB=1) is in the time domain andX_(CB=1) is the frequency domain.

Symbol 304 may be composed of the structure: {CP_(CB=1), x_(CB=1)}, andthe symbol 306 may be composed of the structure: {−CP_(CB=1),−x_(CB=1)}, and CP_(CB=1)=X_(CB=1)(end—No): end) as shown in FIG. 3A,where CP defines the cyclic prefix and No) defines the length of the CP.

The total duration may be equal to 1280 samples @ 2.64 GHz as comparedto the legacy IEEE 802.11ad, which has a length equal to 1728 samples @2.64 GHz, resulting in a 1.35 times shorter duration.

In one embodiment, and in a second option, the second OFDM symbol is anexact copy of the first OFDM symbol. FIG. 3B shows the SISO EDMG-CEFstructure for the OFDM PHY in the time domain in a second option, wherethe second OFDM symbol (e.g., symbol 310) represents an exact copy ofthe first OFDM symbol (e.g., symbol 308). It is understood that theabove descriptions are for purposes of illustration and are not meant tobe limiting.

FIGS. 4A-4B depict illustrative schematic diagrams for an optimizedchannel estimation field system, in accordance with one or more exampleembodiments of the present disclosure.

Referring to FIG. 4A, there is shown a structure of a channel estimationsymbol having a first part and a second part. This first part may be acyclic prefix (CP), and the second part may be a sequence definitionassociated with each stream. For example, a channel estimation symbol(e.g., CE_(n)), is associated with the n^(th) stream. It should beunderstood that the reference to stream is a reference to a space-timestream that may carry information between a transmitting device and areceiving device based on antenna beamforming.

Referring to FIG. 4B, examples of an EDMG-CEF and P matrix for fourspace-time streams (N_(STS)=4) are shown. Each entity in FIG. 4Brepresents a single OFDM symbol defined using the n^(th) sequence of theset. The P matrix can be defined as an arbitrary orthogonal matrix. Itshould be understood that although only four streams are shown, themechanisms described may also be applicable to a larger number ofstreams.

In one embodiment, the optimized channel estimation field system mayfacilitate generation of an MIMO EDMG-CEF field for OFDM on thetransmitting device. When the receiving device receives the symbolsassociated with the EDMG-CEF fields received from the transmittingdevice, the receiving device may be able to determine the channelestimation symbols (e.g., CE1, CE2, CE3, and CE4) based on how thestructure was generated on the transmitting device. For MIMO, thestructure may be generalized for any number of streams by selecting thesize of the structure in accordance with an orthogonal P matrix to coveras many streams as possible. It should be understood that IEEE 802.11addoes not have MIMO support, and the sequence is defined in the timedomain.

In one embodiment, an optimized channel estimation system may usemutually orthogonal sequences for the channel estimation fieldsassociated with the various streams. In IEEE 802.11 n/ac, a singlesequence is used, where cyclic shift diversity is applied to preventcoherent transmissions between different streams. In other words, IEEE802.11 n/ac use only one sequence of pilots in the frequency domain andthen that sequence is transferred to the time domain using IDFT.Consequently, in order to get different signals in the time domain fordifferent streams, cyclic shift diversity is applied in the time domain.

In one embodiment, an optimized channel estimation system, on thetransmitting device, and a set of sequences of pilots in the frequencydomain may be defined such that the sequences in the set are differentfrom each other within the frequency domain even before transferring thesequences to the time domain using IDFT. Consequently, when thesesequences are transferred to the time domain using IDFT, different timedomain sequences are generated without the need to utilize cyclic shiftdiversity to differentiate the different streams. This is because thesequences were different in the frequency domain even before applyingthe IDFT.

As shown in FIG. 4B, if only one stream is used between the transmittingdevice and the receiving device, the symbols received during timeslotsT1 and T2 (e.g., symbols 406) may be enough for the receiving device todetermine the channel estimation associated with that stream. This issimilar to the SISO scenario described in FIGS. 3A and 3B. In thesymbols 406, there is shown the scenario where the second symbol (e.g.,the symbol during T2) is the inverse of the first symbol (e.g., thesymbol during T1). The receiving device may be able to determine, basedon these two received symbols what the channel estimation is.

In another example where two streams are established between thetransmitting device and the receiving device, the channel estimationsymbols (e.g., symbols 408) received during timeslots T1 and T2, whereT2 is subsequent to T1 in the time domain may be needed in order todetermine the channel estimation for stream one and stream two. Forexample, having two streams, the receiving device may receive CE1+CE2during T1. During T2, the receiving device may receive −CE1+CE2 as shownin FIG. 4B. In order to extract CE2, the received sum (e.g., CE1+CE2)during T1 is added to the received difference (e.g., −CE1+CE2) duringT2. That is, [CE1+CE2]−[−CE1+CE2]=2CE2. Therefore, the channelestimation of the second stream is determined, and the receiving deviceis able to utilize the channel estimation for the second stream whenreceiving other frames on that stream. In a similar manner, in order toextract CE1, the received sum during T1 is subtracted from the receivedsum during T2. That is, [CE1+CE2]−[−CE1+CE2]=2CE1. Therefore, thechannel estimation of the first stream is determined, and the receivingdevice is able to utilize the channel estimation for the first streamwhen receiving other frames on that stream. A similar mechanism may beapplied based on the number of streams needed. This mechanism willensure that the receiver is able to separate the streams.

In one embodiment, in order to extract the channel estimations for threestreams, the receiving device may wait until it receives all thecombined channel estimations during timeslots T1, T2, T3, and T4. Inthat case, the structure shown in FIG. 4B is used, where an invertedchannel estimation symbol is sent by the transmitting device at certaintimeslots in order for the receiving device to be able to performsubtraction or addition to determine the channel estimation of eachstrain. For example, the receiving device may perform addition andsubtraction operations between symbols 410 received in timeslots T1, T2,T3, and T4 in order to extract CE1, CE2 and CE3.

In one embodiment, the optimized channel estimation system mayfacilitate the generation of an EDMG-CEF field in MIMO based on a Porthogonal sign matrix. In this case, the optimized channel estimationsystem may determine different sequences for different streams.Consequently, sequences {x_(n)}, where n=1:N_(STS) may be determined onthe transmitting device, which are based on the frequency domain and notcyclic shift diversity as was done in the IEEE 802.11ac standard. Itshould be noted that N_(STS) is associated with a number of space-timestreams.

In one embodiment, an optimized channel estimation system may constructa sequence set. Different streams have different sequences. For example,CE1 is composed of one OFDM symbol. The OFDM symbol is defined in thefrequency domain as was described previously, where a sequence isdefined using sequence A and sequence B on the left and the right sideof the DC subcarriers. That is, CE1 uses a first sequence (having itsown sequences A and B), and CE2 uses a second sequence (having its ownsequences A and B), and so on. Therefore, each stream uses its ownsequence, where the sequences are defined in the frequency domain, andthe index n defines the stream number.

In order to define each sequence of a channel estimation symbol (e.g.,CE1), sequence A and sequence B may be determined, where sequence A isfor the left side of the spectrum, and sequence B is for the right sideof the spectrum. Sequence A and sequence B may be defined using amodulation alphabet, which consists of four different signalingalternatives and may be illustrated as having four different points in atwo-dimensional plane. This provides for a simple channel estimation.That is, when the receiving device receives the symbols, it multipliesthe pilots by the channel. In order to extract the channel coefficients,a division by the pilot value may be performed. Therefore, if the pilotvalue is +1 or −1, +j or −j, there is no need for the divisionimplementation.

In one embodiment, an optimized channel estimation system may generatethe sequence set design by applying the following mechanism:

A frequency domain pilot sequence {SeqA_(n), SeqB_(n)} for the n^(th)space-time stream, n=1:N_(STS), is defined using the {±1, ±j} alphabet.This may allow simple channel estimation by avoiding implementation ofthe division operation explained above. The Peak to Average Power Ratio(PAPR) for each sequence {SeqA_(n), SeqB_(n)} in the set should be lessor equal to 3.0 dB. A low PAPR value may allow channel estimation in the“linear” power amplifier regime and may minimize the non-lineardistortion of the resulting channel estimation. All frequency domainpilot sequences {SeqA_(n), SeqB_(n)}, n=1:N_(STS), are mutuallyorthogonal. This may avoid unintentional beamforming.

In one embodiment, the sequence set {SeqA_(n), SeqB_(n)}, n=1:N_(STS)for MIMO is constructed applying the iterative procedure describedbelow:

The iteration process starts from the basic sequences A⁽⁰⁾ and B⁽⁰⁾defined using the {±1, ±j} alphabet:

-   -   A⁽⁰⁾={+1, +j, +j, −1, −j, +j, −1, +1, −1, +j, +1}, having a        length of 11.    -   B⁽⁰⁾={−1, +1, −1, +j, +1, +1, −j, −j, −j, +1, +1}, having a        length of 11.

The iterative procedure for the n^(th) sequence is defined as follows:

-   -   A_(n) ^((k))={W(n, k)*A_(n) ^((k-1)), B_(n) ^((k-1))};    -   B_(n) ^((k))={W(n, k)*A_(n) ^((k-1)); −B_(n) ^((k-1))}; where        “k” defines the iteration index.

To achieve the sequence length for A and B of 176 symbols, one needs tomake 4 iterations, k=1, 2, 3, 4, which will give 176=16*11.

Performing the first iteration may be determined using the previousiteration of sequence A multiplied by a weight vector W and merged bythe sequence B at the end. For the B sequence, it has the same firstpart as the sequence A, however, it is merged with an inverse ofsequence B at the end. Performing four iterations will result in therequired length of sequence A and sequence B.

Different weight vectors W may be defined to generate differentsequences. Using a different weight Vector W results in generating adifferent sequence A and sequence B. Consequently, each stream wouldresult in having different sequences A and B and therefore differentchannel estimation. The column defines the iteration, and the rowdefines the stream number. Four iterations may be needed to get therequired length of 176. The choices of the weight vector W allows thatthe PAPR meets the required thresholds (<=3 dB). This also allows fororthogonality between different streams; that is, orthogonality betweenthe pairs of sequences A and B of one stream and another pairs ofsequences A and B of another stream. After IDFT is applied to each pair,orthogonality between the time domain sequences may be preserved,because DFT is a unitary transformation. Although a length of 11 forsequence A⁽⁰⁾ and B⁽⁰⁾ was used, a length of 176 for sequence A andsequence B is needed in order to complete the spectrum definition of anOFDM signal, which is composed of 352 occupied (336 data+16 pilots) and160 zero subcarriers, so in total 512 subcarriers.

The sequences SeqA_(n) and SeqB_(n) are defined as follows:

-   -   SeqA_(n)=A_(n) ⁽⁴⁾; SeqB_(n)=B_(n) ⁽⁴⁾;

The weight matrix W is defined as follows:

$\begin{matrix}{W =} & \{ {{+ 1},{- 1},{+ j},{{- j};}}  \\\; & {{- j},{+ 1},{- j},{{- j};}} \\\; & {{+ 1},{- j},{+ 1},{{- j};}} \\\; & {{- 1},{+ 1},{- 1},{{+ j};}} \\\; & {{+ 1},{+ j},{- 1},{{- j};}} \\\; & {{- 1},{+ j},{+ 1},{{- j};}} \\\; & {{+ j},{- j},{- j},{{- j};}} \\\; & {1,{+ 1},{+ j},{{- j};}} \\\; & {{- 1},{- 1},{- j},{{- j};}} \\\; & {{- j},{- j},{- j},{{- j};}} \\\; & {{+ j},{+ 1},{+ j},{{- j};}} \\\; & {{- j},{+ 1},{+ 1},{{- j};}} \\\; & {{- 1},{+ j},{- j},{{- j};}} \\\; & {{+ j},{- j},{+ 1},{{- j};}} \\\; & {{- j},{+ 1},{- 1},{{- j};}} \\\; & { {{- j},{- 1},{- j},{- j}} \}.}\end{matrix}$

A row vector in matrix W defines the weight vector for a given sequencewith index “n.” A column vector in matrix W defines the weights over allsequences in the set for the given iteration with index “k.” Therefore,this procedure can produce sequences for N_(STS)=16 streams. In case ofMU-MIMO, 16 streams may be used, so in that case all rows of matrix Wmay be in use. It should be understood that any subset of the W rows maybe used to produce the sequences.

In one embodiment, a requirement may be to have the PAPR≤3.0 dB. Table 1below provides a summary of PAPR properties of the designed sequence setin accordance with one or more embodiments of the optimized channelestimation system. The legacy DMG-CEF PAPR is equal to ˜3.12 dB. Hence,the EDMG-CEF sequence set of the optimized channel estimation system hasgood PAPR properties. It is understood that the above descriptions arefor purposes of illustration and are not meant to be limiting.

TABLE 1 Stream # W vector PAPR, [dB] 1 [+1, −1, +j, −j] 2.9775 2 [−j,+1, −j, −j] 2.9788 3 [+1, −j, +1, −j] 2.9800 4 [−1, +1, −1, −j] 2.9800 5[+1, +j, −1, −j] 2.9838 6 [−1, +j, +1, −j] 2.9845 7 [+j, −j, −j, −j]2.9886 8 [+1, +1, +j, −j] 2.9923 9 [−1, −1, −j, −j] 2.9923 10 [−j, −j,−j, −j] 2.9944 11 [+j, +1, +j, −j] 2.9944 12 [−j, +1, +1, −j] 2.9951 13[−1, +j, −j, −j] 2.9966 14 [+j, −j, +1, −j] 2.9975 15 [−j, +1, −1, −j]2.9975 16 [−j, −1, −j, −j] 2.9992

FIG. 5A illustrates a flow diagram of an illustrative process 500 for anillustrative optimized channel estimation field system, in accordancewith one or more example embodiments of the present disclosure.

At block 502, a device (e.g., the user device(s) 120 and/or the AP 102of FIG. 1) may determine an EDMG frame to be sent to another device(e.g., the user device(s) 120 and/or the AP 102 of FIG. 1) using atleast one spatial stream. It should be understood that the reference tostream is a reference to a space-time stream that may carry informationbetween a transmitting device and a receiving device based on antennabeamforming. Mutually orthogonal sequences for the channel estimationfields associated with the various streams may be generated by thedevice. In a legacy device, a single sequence is used, where cyclicshift diversity is applied to prevent coherent transmissions betweendifferent streams. In other words, legacy devices use only one sequenceof pilots in the frequency domain and then that sequence is transferredto the time domain using IDFT. Consequently, in order to get differentsignals in the time domain for different streams, cyclic shift diversityis applied in the time domain. The device may define a set of sequencesof pilots in the frequency domain such that the sequences in the set aredifferent from each other within the frequency domain even beforetransferring the sequences to the time domain using IDFT. Consequently,when these sequences are transferred to the time domain using IDFT,different time domain sequences are generated without the need toutilize cyclic shift diversity to differentiate the different streams.This is because the sequences were different in the frequency domaineven before applying the IDFT. In addition, the sequences may beselected in order to provide low PAPR after application of inversediscrete Fourier transform (IDFT) transformation in the time domain. Forexample, the PAPR should be less or equal to 3.0 dB.

At block 504, the device may determine a channel estimation field (CEF)included in the EDMG frame, wherein the CEF is comprised of one or morefrequency division multiplexing (OFDM) symbols. The device may determinethe CEF for SISO and/or for MIMO. For SISO, the CEF may be composed oftwo OFDM symbols. For MIMO, the general structure of the CEF may becomposed of two OFDM symbols having a set of sequences such thatdifferent streams have different sequences. In the SISO and MIMO case,the first symbol may be related to the second symbol such that in onecase the second symbol is the inverse of the first symbol and in anothercase, the second symbol is the exact copy of the first symbol.

At block 506, the device may cause to send the EDMG frame to the firstdevice using the at least one spatial stream. The one or more spatialstreams refer to one or more space-time streams that may carryinformation between a transmitting device and a receiving device basedon antenna beamforming. For example, in the SISO case, there may be onlyone stream between a transmitting device and a receiving device.Consequently, the EDMG frame may be sent on that stream. In the MIMOcase, there may be multiple streams between the transmitting device andthe receiving device.

FIG. 5B illustrates a flow diagram of an illustrative process 550 for ahigh efficiency signal field coding system, in accordance with one ormore example embodiments of the present disclosure.

At block 552, a device (e.g., the user device(s) 120 and/or the AP 102of FIG. 1) may identify one or more first channel estimation symbolsreceived on one or more streams during a first timeslot (e.g., T1). Whenthe device receives the symbols, which are associated with the EDMG-CEFfields received from the transmitting device (e.g., AP 102), the devicemay be able to determine the channel estimation symbols based on how thestructure was generated on the transmitting device. For MIMO, thestructure may be generalized for any number of streams by selecting thesize of the structure in accordance with an orthogonal P matrix to coveras many streams as possible.

At block 554, the device may identify one or more second channelestimation symbols received on the one or more streams during a secondtimeslot (e.g., T2). For example, if only one stream is used between thetransmitting device and the receiving device, the symbols receivedduring timeslots T1 and T2 may be enough for the receiving device todetermine the channel estimation associated with that stream. This issimilar to the SISO scenario described in FIGS. 3A and 3B, where in onecase the second symbol (e.g., the symbol during T2) is the inverse ofthe first symbol (e.g., the symbol during T1). The receiving device maybe able to determine, based on these two received symbols, what thechannel estimation is.

At block 556, the device may combine the one or more first channelestimation symbols and the one or more second channel estimationsymbols. For example, if at T1, the receiving device receives CE1 and attime T2, the receiving device receives a second symbol that is the exactcopy of CE1, then it is able to determine the channel estimation basedon the sum of the two symbols at the two timeslots (e.g., 2CE1). In casethe two symbols were the inverse of each other, then subtracting fromeach other results in 2CE1. In case two streams are established betweenthe transmitting device and the receiving device, the channel estimationsymbols received during timeslots T1 and T2, where T2 is subsequent toT1 in the time domain, may be needed in order to determine the channelestimation for stream one and stream two. For example, having twostreams, the receiving device may receive CE1+CE2 during T1. During T2,the receiving device may receive −CE1+CE2 as shown in FIG. 4B. In orderto extract CE2, the received sum (e.g., CE1+CE2) during T1 is added tothe received difference (e.g., −CE1+CE2) during T2. That is,[CE1+CE2]−[−CE1+CE2]=2CE2. Therefore, the channel estimation of thesecond stream is determined, and the receiving device is able to utilizethe channel estimation for the second stream when receiving other frameson that stream. In a similar manner, in order to extract CE1, thereceived sum during T1 is subtracted from the received sum during T2.That is, [CE1+CE2]−[−CE1+CE2]=2CE1. Therefore, the channel estimation ofthe first stream is determined, and the receiving device is able toutilize the channel estimation for the first stream when receiving otherframes on that stream. A similar mechanism may be applied based on thenumber of streams needed. This mechanism will ensure that the receiveris able to separate the streams.

At block 558, the device may determine at least one of the one or morefirst channel estimation symbols based at least in part on thecombination. Based on the above calculations, the receiving device maybe able to determine the two symbols associated with the channelestimation field (CEF) to ensure that the receiver is able to separatethe streams using the channel estimations on a stream basis. It isunderstood that the above descriptions are for purposes of illustrationand are not meant to be limiting.

FIG. 6 shows a functional diagram of an exemplary communication station600 in accordance with some embodiments. In one embodiment, FIG. 6illustrates a functional block diagram of a communication station thatmay be suitable for use as an AP 102 (FIG. 1) or a user device 120(FIG. 1) in accordance with some embodiments. The communication station600 may also be suitable for use as a handheld device, a mobile device,a cellular telephone, a smartphone, a tablet, a netbook, a wirelessterminal, a laptop computer, a wearable computer device, a femtocell, ahigh data rate (HDR) subscriber station, an access point, an accessterminal, or other personal communication system (PCS) device.

The communication station 600 may include communications circuitry 602and a transceiver 610 for transmitting and receiving signals to and fromother communication stations using one or more antennas 601. Thecommunications circuitry 602 may include circuitry that can operate thephysical layer (PHY) communications and/or media access control (MAC)communications for controlling access to the wireless medium, and/or anyother communications layers for transmitting and receiving signals. Thecommunication station 600 may also include processing circuitry 606 andmemory 608 arranged to perform the operations described herein. In someembodiments, the communications circuitry 602 and the processingcircuitry 606 may be configured to perform operations detailed in FIGS.1-5.

In accordance with some embodiments, the communications circuitry 602may be arranged to contend for a wireless medium and configure frames orpackets for communicating over the wireless medium. The communicationscircuitry 602 may be arranged to transmit and receive signals. Thecommunications circuitry 602 may also include circuitry formodulation/demodulation, upconversion/downconversion, filtering,amplification, etc. In some embodiments, the processing circuitry 606 ofthe communication station 600 may include one or more processors. Inother embodiments, two or more antennas 601 may be coupled to thecommunications circuitry 602 arranged for sending and receiving signals.The memory 608 may store information for configuring the processingcircuitry 606 to perform operations for configuring and transmittingmessage frames and performing the various operations described herein.The memory 608 may include any type of memory, including non-transitorymemory, for storing information in a form readable by a machine (e.g., acomputer). For example, the memory 608 may include a computer-readablestorage device, read-only memory (ROM), random-access memory (RAM),magnetic disk storage media, optical storage media, flash-memory devicesand other storage devices and media.

In some embodiments, the communication station 600 may be part of aportable wireless communication device, such as a personal digitalassistant (PDA), a laptop or portable computer with wirelesscommunication capability, a web tablet, a wireless telephone, asmartphone, a wireless headset, a pager, an instant messaging device, adigital camera, an access point, a television, a medical device (e.g., aheart rate monitor, a blood pressure monitor, etc.), a wearable computerdevice, or another device that may receive and/or transmit informationwirelessly.

In some embodiments, the communication station 600 may include one ormore antennas 601. The antennas 601 may include one or more directionalor omnidirectional antennas, including, for example, dipole antennas,monopole antennas, patch antennas, loop antennas, microstrip antennas,or other types of antennas suitable for transmission of RF signals. Insome embodiments, instead of two or more antennas, a single antenna withmultiple apertures may be used. In these embodiments, each aperture maybe considered a separate antenna. In some multiple-input multiple-output(MIMO) embodiments, the antennas may be effectively separated forspatial diversity and the different channel characteristics that mayresult between each of the antennas and the antennas of a transmittingstation.

In some embodiments, the communication station 600 may include one ormore of a keyboard, a display, a non-volatile memory port, multipleantennas, a graphics processor, an application processor, speakers, andother mobile device elements. The display may be an LCD screen includinga touch screen.

Although the communication station 600 is illustrated as having severalseparate functional elements, two or more of the functional elements maybe combined and may be implemented by combinations ofsoftware-configured elements, such as processing elements includingdigital signal processors (DSPs), and/or other hardware elements. Forexample, some elements may include one or more microprocessors, DSPs,field-programmable gate arrays (FPGAs), application specific integratedcircuits (ASICs), radio-frequency integrated circuits (RFICs) andcombinations of various hardware and logic circuitry for performing atleast the functions described herein. In some embodiments, thefunctional elements of the communication station 600 may refer to one ormore processes operating on one or more processing elements.

Certain embodiments may be implemented in one or a combination ofhardware, firmware, and software. Other embodiments may also beimplemented as instructions stored on a computer-readable storagedevice, which may be read and executed by at least one processor toperform the operations described herein. A computer-readable storagedevice may include any non-transitory memory mechanism for storinginformation in a form readable by a machine (e.g., a computer). Forexample, a computer-readable storage device may include read-only memory(ROM), random-access memory (RAM), magnetic disk storage media, opticalstorage media, flash-memory devices, and other storage devices andmedia. In some embodiments, the communication station 600 may includeone or more processors and may be configured with instructions stored ona computer-readable storage device memory.

FIG. 7 illustrates a block diagram of an example of a machine 700 orsystem upon which any one or more of the techniques (e.g.,methodologies) discussed herein may be performed. In other embodiments,the machine 700 may operate as a standalone device or may be connected(e.g., networked) to other machines. In a networked deployment, themachine 700 may operate in the capacity of a server machine, a clientmachine, or both in server-client network environments. In an example,the machine 700 may act as a peer machine in peer-to-peer (P2P) (orother distributed) network environments. The machine 700 may be apersonal computer (PC), a tablet PC, a set-top box (STB), a personaldigital assistant (PDA), a mobile telephone, a wearable computer device,a web appliance, a network router, a switch or bridge, or any machinecapable of executing instructions (sequential or otherwise) that specifyactions to be taken by that machine, such as a base station. Further,while only a single machine is illustrated, the term “machine” shallalso be taken to include any collection of machines that individually orjointly execute a set (or multiple sets) of instructions to perform anyone or more of the methodologies discussed herein, such as cloudcomputing, software as a service (SaaS), or other computer clusterconfigurations.

Examples, as described herein, may include or may operate on logic or anumber of components, modules, or mechanisms. Modules are tangibleentities (e.g., hardware) capable of performing specified operationswhen operating. A module includes hardware. In an example, the hardwaremay be specifically configured to carry out a specific operation (e.g.,hardwired). In another example, the hardware may include configurableexecution units (e.g., transistors, circuits, etc.) and a computerreadable medium containing instructions where the instructions configurethe execution units to carry out a specific operation when in operation.The configuring may occur under the direction of the executions units ora loading mechanism. Accordingly, the execution units arecommunicatively coupled to the computer-readable medium when the deviceis operating. In this example, the execution units may be a member ofmore than one module. For example, under operation, the execution unitsmay be configured by a first set of instructions to implement a firstmodule at one point in time and reconfigured by a second set ofinstructions to implement a second module at a second point in time.

The machine (e.g., computer system) 700 may include a hardware processor702 (e.g., a central processing unit (CPU), a graphics processing unit(GPU), a hardware processor core, or any combination thereof), a mainmemory 704 and a static memory 706, some or all of which may communicatewith each other via an interlink (e.g., bus) 708. The machine 700 mayfurther include a power management device 732, a graphics display device710, an alphanumeric input device 712 (e.g., a keyboard), and a userinterface (UI) navigation device 714 (e.g., a mouse). In an example, thegraphics display device 710, alphanumeric input device 712, and UInavigation device 714 may be a touch screen display. The machine 700 mayadditionally include a storage device (i.e., drive unit) 716, a signalgeneration device 718 (e.g., a speaker), a OFDMA uplink resourceallocation device 719, a network interface device/transceiver 720coupled to antenna(s) 730, and one or more sensors 728, such as a globalpositioning system (GPS) sensor, a compass, an accelerometer, or othersensor. The machine 700 may include an output controller 734, such as aserial (e.g., universal serial bus (USB), parallel, or other wired orwireless (e.g., infrared (IR), near field communication (NFC), etc.)connection to communicate with or control one or more peripheral devices(e.g., a printer, a card reader, etc.)).

The storage device 716 may include a machine readable medium 722 onwhich is stored one or more sets of data structures or instructions 724(e.g., software) embodying or utilized by any one or more of thetechniques or functions described herein. The instructions 724 may alsoreside, completely or at least partially, within the main memory 704,within the static memory 706, or within the hardware processor 702during execution thereof by the machine 700. In an example, one or anycombination of the hardware processor 702, the main memory 704, thestatic memory 706, or the storage device 716 may constitutemachine-readable media.

The optimized channel estimation field device 719 may carry out orperform any of the operations and processes (e.g., the processes 500 and550) described and shown above. For example, the optimized channelestimation field device 719 may facilitate a design of a channelestimation field (CEF) for EDMG OFDM for the physical layer (PHY). Theoptimized channel estimation field device 719 may cover SISO and MIMOsingle channel transmission.

In one embodiment, the optimized channel estimation field device 719 maydetermine the EDMG CEF to be comprised of two OFDM symbols. In oneoption, the second symbol may have an inverted sign polarity compared tothe first symbol. In another option, the second OFDM symbol mayrepresent an exact copy of the first OFDM symbol.

The optimized channel estimation field device 719 may define pilotsequences in the frequency domain, rather than the time domain Golaysequences defined in the IEEE 802.11ad standard.

The optimized channel estimation field device 719 may facilitate amutually orthogonal sequence set, instead of using cyclic shiftdiversity (CSD) as was done in legacy devices (e.g., IEEE 802.11n/ac).The orthogonality property of the sequences prevents the coherent signaltransmission of different space-time streams in the case of MIMO andavoids unintentional beamforming.

It is understood that the above are only a subset of what the optimizedchannel estimation field device 719 may be configured to perform andthat other functions included throughout this disclosure may also beperformed by the optimized channel estimation field device 719.

While the machine-readable medium 722 is illustrated as a single medium,the term “machine-readable medium” may include a single medium ormultiple media (e.g., a centralized or distributed database, and/orassociated caches and servers) configured to store the one or moreinstructions 724.

Various embodiments may be implemented fully or partially in softwareand/or firmware. This software and/or firmware may take the form ofinstructions contained in or on a non-transitory computer-readablestorage medium. Those instructions may then be read and executed by oneor more processors to enable performance of the operations describedherein. The instructions may be in any suitable form, such as but notlimited to source code, compiled code, interpreted code, executablecode, static code, dynamic code, and the like. Such a computer-readablemedium may include any tangible non-transitory medium for storinginformation in a form readable by one or more computers, such as but notlimited to read only memory (ROM); random access memory (RAM); magneticdisk storage media; optical storage media; a flash memory, etc.

The term “machine-readable medium” may include any medium that iscapable of storing, encoding, or carrying instructions for execution bythe machine 700 and that cause the machine 700 to perform any one ormore of the techniques of the present disclosure, or that is capable ofstoring, encoding, or carrying data structures used by or associatedwith such instructions. Non-limiting machine-readable medium examplesmay include solid-state memories and optical and magnetic media. In anexample, a massed machine-readable medium includes a machine-readablemedium with a plurality of particles having resting mass. Specificexamples of massed machine-readable media may include non-volatilememory, such as semiconductor memory devices (e.g., electricallyprogrammable read-only memory (EPROM), or electrically erasableprogrammable read-only memory (EEPROM)) and flash memory devices;magnetic disks, such as internal hard disks and removable disks;magneto-optical disks; and CD-ROM and DVD-ROM disks.

The instructions 724 may further be transmitted or received over acommunications network 726 using a transmission medium via the networkinterface device/transceiver 720 utilizing any one of a number oftransfer protocols (e.g., frame relay, internet protocol (IP),transmission control protocol (TCP), user datagram protocol (UDP),hypertext transfer protocol (HTTP), etc.). Example communicationsnetworks may include a local area network (LAN), a wide area network(WAN), a packet data network (e.g., the Internet), mobile telephonenetworks (e.g., cellular networks), plain old telephone (POTS) networks,wireless data networks (e.g., Institute of Electrical and ElectronicsEngineers (IEEE) 802.11 family of standards known as Wi-Fi®, IEEE 802.16family of standards known as WiMax®), IEEE 802.15.4 family of standards,and peer-to-peer (P2P) networks, among others. In an example, thenetwork interface device/transceiver 720 may include one or morephysical jacks (e.g., Ethernet, coaxial, or phone jacks) or one or moreantennas to connect to the communications network 726. In an example,the network interface device/transceiver 720 may include a plurality ofantennas to wirelessly communicate using at least one of single-inputmultiple-output (SIMO), multiple-input multiple-output (MIMO), ormultiple-input single-output (MISO) techniques. The term “transmissionmedium” shall be taken to include any intangible medium that is capableof storing, encoding, or carrying instructions for execution by themachine 700 and includes digital or analog communications signals orother intangible media to facilitate communication of such software. Theoperations and processes (e.g., processes 500 and 550) described andshown above may be carried out or performed in any suitable order asdesired in various implementations. Additionally, in certainimplementations, at least a portion of the operations may be carried outin parallel. Furthermore, in certain implementations, less than or morethan the operations described may be performed.

The word “exemplary” is used herein to mean “serving as an example,instance, or illustration.” Any embodiment described herein as“exemplary” is not necessarily to be construed as preferred oradvantageous over other embodiments. The terms “computing device,” “userdevice,” “communication station,” “station,” “handheld device,” “mobiledevice,” “wireless device” and “user equipment” (UE) as used hereinrefers to a wireless communication device such as a cellular telephone,a smartphone, a tablet, a netbook, a wireless terminal, a laptopcomputer, a femtocell, a high data rate (HDR) subscriber station, anaccess point, a printer, a point of sale device, an access terminal, orother personal communication system (PCS) device. The device may beeither mobile or stationary.

As used within this document, the term “communicate” is intended toinclude transmitting, or receiving, or both transmitting and receiving.This may be particularly useful in claims when describing theorganization of data that is being transmitted by one device andreceived by another, but only the functionality of one of those devicesis required to infringe the claim. Similarly, the bidirectional exchangeof data between two devices (both devices transmit and receive duringthe exchange) may be described as “communicating,” when only thefunctionality of one of those devices is being claimed. The term“communicating” as used herein with respect to a wireless communicationsignal includes transmitting the wireless communication signal and/orreceiving the wireless communication signal. For example, a wirelesscommunication unit, which is capable of communicating a wirelesscommunication signal, may include a wireless transmitter to transmit thewireless communication signal to at least one other wirelesscommunication unit, and/or a wireless communication receiver to receivethe wireless communication signal from at least one other wirelesscommunication unit.

As used herein, unless otherwise specified, the use of the ordinaladjectives “first,” “second,” “third,” etc., to describe a commonobject, merely indicates that different instances of like objects arebeing referred to and are not intended to imply that the objects sodescribed must be in a given sequence, either temporally, spatially, inranking, or in any other manner.

The term “access point” (AP) as used herein may be a fixed station. Anaccess point may also be referred to as an access node, a base station,or some other similar terminology known in the art. An access terminalmay also be called a mobile station, user equipment (UE), a wirelesscommunication device, or some other similar terminology known in theart. Embodiments disclosed herein generally pertain to wirelessnetworks. Some embodiments may relate to wireless networks that operatein accordance with one of the IEEE 802.11 standards.

Some embodiments may be used in conjunction with various devices andsystems, for example, a personal computer (PC), a desktop computer, amobile computer, a laptop computer, a notebook computer, a tabletcomputer, a server computer, a handheld computer, a handheld device, apersonal digital assistant (PDA) device, a handheld PDA device, anon-board device, an off-board device, a hybrid device, a vehiculardevice, a non-vehicular device, a mobile or portable device, a consumerdevice, a non-mobile or non-portable device, a wireless communicationstation, a wireless communication device, a wireless access point (AP),a wired or wireless router, a wired or wireless modem, a video device,an audio device, an audio-video (A/V) device, a wired or wirelessnetwork, a wireless area network, a wireless video area network (WVAN),a local area network (LAN), a wireless LAN (WLAN), a personal areanetwork (PAN), a wireless PAN (WPAN), and the like.

Some embodiments may be used in conjunction with one way and/or two-wayradio communication systems, cellular radio-telephone communicationsystems, a mobile phone, a cellular telephone, a wireless telephone, apersonal communication system (PCS) device, a PDA device whichincorporates a wireless communication device, a mobile or portableglobal positioning system (GPS) device, a device which incorporates aGPS receiver or transceiver or chip, a device which incorporates an RFIDelement or chip, a multiple input multiple output (MIMO) transceiver ordevice, a single input multiple output (SIMO) transceiver or device, amultiple input single output (MISO) transceiver or device, a devicehaving one or more internal antennas and/or external antennas, digitalvideo broadcast (DVB) devices or systems, multi-standard radio devicesor systems, a wired or wireless handheld device, e.g., a smartphone, awireless application protocol (WAP) device, or the like.

Some embodiments may be used in conjunction with one or more types ofwireless communication signals and/or systems following one or morewireless communication protocols, for example, radio frequency (RF),infrared (IR), frequency-division multiplexing (FDM), orthogonal FDM(OFDM), time-division multiplexing (TDM), time-division multiple access(TDMA), extended TDMA (E-TDMA), general packet radio service (GPRS),extended GPRS, code-division multiple access (CDMA), wideband CDMA(WCDMA), CDMA 2000, single-carrier CDMA, multi-carrier CDMA,multi-carrier modulation (MDM), discrete multi-tone (DMT), Bluetooth®,global positioning system (GPS), Wi-Fi, Wi-Max, ZigBee, ultra-wideband(UWB), global system for mobile communications (GSM), 2G, 2.5G, 3G,3.5G, 4G, fifth generation (5G) mobile networks, 3GPP, long termevolution (LTE), LTE advanced, enhanced data rates for GSM Evolution(EDGE), or the like. Other embodiments may be used in various otherdevices, systems, and/or networks.

According to example embodiments of the disclosure, there may be adevice. The device may include memory and processing circuitryconfigured to determine an enhanced directional multi-gigabit (EDMG)frame to be sent to a first device using at least one spatial stream.The memory and processing circuitry may be further configured todetermine a channel estimation field (CEF) to be included in the EDMGframe, wherein the CEF is comprised of one or more frequency divisionmultiplexing (OFDM) symbols. The memory and processing circuitry may befurther configured to cause to send the EDMG frame to the first deviceusing the at least one spatial stream.

The implementations may include one or more of the following features.The one or more OFDM symbols include at least in part a first symbol anda second symbol, wherein the second symbol that has an inverted polaritysign to the first symbol. The one or more OFDM symbols include at leastin part a first symbol and a second symbol, wherein the second symbol isthe same as the first symbol. The one or more spatial streams areassociated with a single-input single-output (SISO) or a multiple-inputmultiple-output (MIMO) single channel transmission. The first symbol iscomprised of one or more pilot sequences, wherein the one or more pilotsequences are defined in a frequency domain. The memory and theprocessing circuitry are further configured to determine the firstsymbol to be comprised of at least in part a first sequence having aninitial first sequence, and a second sequence having an initial secondsequence, wherein the first sequence and the second sequence aredetermined by performing one or more iterations. The memory and theprocessing circuitry are further configured to determine a firstiteration of the first sequence by multiplying the initial firstsequence by a weight vector and adding that to the initial secondsequence. The memory and processing circuitry may be further configuredto determine a first iteration of the second sequence by multiplying theinitial first sequence by the weight vector and adding that to negativevalues of the initial second sequence. The memory and processingcircuitry may be further configured to perform additional iterations toa maximum value of iterations. Performing one or more iterationscomprises determining the first sequence by A_(n) ^((k))={W(n, k)*A_(n)^((k-1)), B_(n) ^((k-1))} wherein A⁽⁰⁾={+1, +j, +j, −1, −j, +j, −1, +1,−1, +j, +1}; and determining the second sequence by B_(n) ^((k))={W(n,k)*A_(n) ^((k-1)), −B_(n) ^((k-1))}; wherein B⁽⁰⁾={−1, +1, −1, +j, +1,+1, −j, −j, −j, +1, +1}, and wherein k is an iteration index, and W(n,k) is a weight vector for the n^(th) stream and the k^(th) iteration.The weight vector W is based on a weight matrix, wherein the weightmatrix has one or more rows and one or more columns, wherein the one ormore rows are associated with a stream number, and the one or morecolumns are associated with a number of iteration of the one or moreiterations, and wherein the weight matrix is defined as

{+1, −1, +j, −j; −j, +1, −j, −j; +1, −j, +1, −j; −1, +1, −1, −j; +1, +j, −1, −j; −1, +j, +1, −j; +j, −j, −j, −j; 1, +1, +j, −j; −1, −1, −j, −j; −j, −j, −j, −j; +j, +1, +j, −j; −j, +1, +1, −j; −1, +j, −j, −j; +j, −j, +1, −j; −j, +1, −1, −j; −j, −1, −j, −j}.

The device may further include a transceiver configured to transmit andreceive wireless signals. The device may further include one or moreantennas coupled to the transceiver.

According to example embodiments of the disclosure, there may be anon-transitory computer-readable medium storing computer-executableinstructions which, when executed by a processor, cause the processor toperform operations. The operations may include identifying one or morefirst channel estimation symbols received on one or more streams duringa first timeslot. The operations may include identifying one or moresecond channel estimation symbols received on the one or more streamsduring a second timeslot. The operations may include combining the oneor more first channel estimation symbols and the one or more secondchannel estimation symbols. The operations may include determining atleast one of the one or more first channel estimation symbols based atleast in part on the combination.

The implementations may include one or more of the following features.The operations further comprise determining a channel estimation field(CEF) comprised of two orthogonal frequency division multiplexing (OFDM)symbols. The operations further comprise identifying a first sequenceAssociated with a first symbol of the one or more first channelestimation symbols. The operations may include identifying a secondsequence Associated with a second symbol of the one or more firstchannel estimation symbols. The first sequence is different from thesecond sequence in a frequency domain. The second symbol has an invertedpolarity sign to the first symbol. The second symbol is the same as thefirst symbol.

According to example embodiments of the disclosure, there may include amethod. The method may include determining, by one or more processors,an enhanced directional multi-gigabit (EDMG) frame to be sent to a firstdevice using at least one spatial stream. The method may includedetermining a channel estimation field (CEF) to be included in the EDMGframe, wherein the CEF is comprised of one or more frequency divisionmultiplexing (OFDM) symbols. The method may include causing to send theEDMG frame to the first device using the at least one spatial stream.

The implementations may include one or more of the following features.The one or more OFDM symbols include at least in part a first symbol anda second symbol, wherein the second symbol that has an inverted polaritysign to the first symbol. The one or more OFDM symbols include at leastin part a first symbol and a second symbol, wherein the second symbol isa copy of the first symbol. The one or more spatial streams areassociated with a single-input single-output (SISO) or a multiple-inputmultiple-output (MIMO) single channel transmission. The first symbol iscomprised of one or more pilot sequences, wherein the one or more pilotsequences are defined in a frequency domain. The method may furtherinclude determining the first symbol to be comprised of at least in parta first sequence having an initial first sequence, and a second sequencehaving an initial second sequence, wherein the first sequence and thesecond sequence are determined by performing one or more iterations. Themethod may further include determining a first iteration of the firstsequence by multiplying the initial first sequence by a weight vectorand adding that to the initial second sequence. The method may includedetermining a first iteration of the second sequence by multiplying theinitial first sequence by the weight vector and adding that to negativevalues of the initial second sequence. The method may include performingadditional iterations to a maximum value of iterations. Performing oneor more iterations may include determining the first sequence by A_(n)^((k))={W(n, k)*A_(n) ^((k-1)), B_(n) ^((k-1))}, wherein A⁽⁰⁾={+1, +j,+j, −1, −j, +j, −1, +1, −1, +j, +1}; and determining the second sequenceby B_(n) ^((k))={W(n, k)*A_(n) ^((k-1)), −B_(n) ^((k-1))}; whereinB⁽⁰⁾={−1, +1, −1, +j, +1, +1, −j, −j, −j, +1, +1}, and wherein k is aniteration index, and W(n, k) is a weight vector for the n^(th) streamand the k^(th) iteration. The weight vector W is based on a weightmatrix, wherein the weight matrix has one or more rows and one or morecolumns, wherein the one or more rows are associated with a streamnumber, and the one or more columns are associated with a number ofiteration of the one or more iterations, and wherein the weight matrixis defined as

{+1, −1, +j, −j; −j, +1, −j, −j; +1, −j, +1, −j; −1, +1, −1, −j; +1, +j, −1, −j; −1 + j, +1, −j; +j, −j, −j, −j; 1, +1, +j, −j; −1, −1, −j, −j; −j, −j, −j, −j; +j, +1, +j, −j; −j, +1, +1, −j; −1, +j, −j, −j; +j, −j, +1, −j; −j, +1, −1, −j; −j, −1, −j, −j}.

In example embodiments of the disclosure, there may be an apparatus. Theapparatus may include means for determining, by one or more processors,an enhanced directional multi-gigabit (EDMG) frame to be sent to a firstdevice using at least one spatial stream. The apparatus may includemeans for determining a channel estimation field (CEF) to be included inthe EDMG frame, wherein the CEF is comprised of one or more frequencydivision multiplexing (OFDM) symbols. The apparatus may include meansfor causing to send the EDMG frame to the first device using the atleast one spatial stream.

The implementations may include one or more of the following features.The one or more OFDM symbols include at least in part a first symbol anda second symbol, wherein the second symbol that has an inverted polaritysign to the first symbol. The one or more OFDM symbols include at leastin part a first symbol and a second symbol, wherein the second symbol isa copy of the first symbol. The one or more spatial streams areassociated with a single-input single-output (SISO) or a multiple-inputmultiple-output (MIMO) single channel transmission. The first symbol iscomprised of one or more pilot sequences, wherein the one or more pilotsequences are defined in a frequency domain. The apparatus may furtherinclude means for determining the first symbol to be comprised of atleast in part a first sequence having an initial first sequence, and asecond sequence having an initial second sequence, wherein the firstsequence and the second sequence are determined by performing one ormore iterations. The apparatus may further include means for determininga first iteration of the first sequence by multiplying the initial firstsequence by a weight vector and adding that to the initial secondsequence. The apparatus may further include means for determining afirst iteration of the second sequence by multiplying the initial firstsequence by the weight vector and adding that to negative values of theinitial second sequence. The apparatus may further include means forperforming additional iterations to a maximum value of iterations. Theapparatus may further include means for determining the first sequenceby A_(n) ^((k))={W(n, k)*A_(n) ^((k-1)), B_(n) ^((k-1))}, whereinA⁽⁰⁾={+1, +j, +j, −1, −j, +j, −1, +1, −1, +j, +1}; and means fordetermining the second sequence by B_(n) ^((k))={W(n, k)*A_(n) ^((k-1)),−B_(n) ^((k-1))}; wherein B⁽⁰⁾={−1, +1, −1, +j, +1, +1, −j, −j, −j, +1,+1}, and wherein k is an iteration index, and W(n, k) is a weight vectorfor the n^(th) stream and the k^(th) iteration. The weight vector W isbased on a weight matrix, wherein the weight matrix has one or more rowsand one or more columns, wherein the one or more rows are associatedwith a stream number, and the one or more columns are associated with anumber of iteration of the one or more iterations, and wherein theweight matrix is defined as

{+1, −1, +j, −j; −j, +1, −j, −j; +1, −j, +1, −j; −1, +1, −1, −j; +1, +j, −1, −j; −1, +j, +1, −j; +j, −j, −j, −j; 1, +1, +j, −j; −1, −1, −j, −j; −j, −j, −j, −j; +j, +1, +j, −j; −j, +1, +1, −j; −1, +j, −j, −j; +j, −j, +1, −j; −j, +1, −1, −j; −j, −1, −j, −j}.

Certain aspects of the disclosure are described above with reference toblock and flow diagrams of systems, methods, apparatuses, and/orcomputer program products according to various implementations. It willbe understood that one or more blocks of the block diagrams and flowdiagrams, and combinations of blocks in the block diagrams and the flowdiagrams, respectively, may be implemented by computer-executableprogram instructions. Likewise, some blocks of the block diagrams andflow diagrams may not necessarily need to be performed in the orderpresented, or may not necessarily need to be performed at all, accordingto some implementations.

These computer-executable program instructions may be loaded onto aspecial-purpose computer or other particular machine, a processor, orother programmable data processing apparatus to produce a particularmachine, such that the instructions that execute on the computer,processor, or other programmable data processing apparatus create meansfor implementing one or more functions specified in the flow diagramblock or blocks. These computer program instructions may also be storedin a computer-readable storage media or memory that may direct acomputer or other programmable data processing apparatus to function ina particular manner, such that the instructions stored in thecomputer-readable storage media produce an article of manufactureincluding instruction means that implement one or more functionsspecified in the flow diagram block or blocks. As an example, certainimplementations may provide for a computer program product, comprising acomputer-readable storage medium having a computer-readable program codeor program instructions implemented therein, said computer-readableprogram code adapted to be executed to implement one or more functionsspecified in the flow diagram block or blocks. The computer programinstructions may also be loaded onto a computer or other programmabledata processing apparatus to cause a series of operational elements orsteps to be performed on the computer or other programmable apparatus toproduce a computer-implemented process such that the instructions thatexecute on the computer or other programmable apparatus provide elementsor steps for implementing the functions specified in the flow diagramblock or blocks.

Accordingly, blocks of the block diagrams and flow diagrams supportcombinations of means for performing the specified functions,combinations of elements or steps for performing the specified functionsand program instruction means for performing the specified functions. Itwill also be understood that each block of the block diagrams and flowdiagrams, and combinations of blocks in the block diagrams and flowdiagrams, may be implemented by special-purpose, hardware-based computersystems that perform the specified functions, elements or steps, orcombinations of special-purpose hardware and computer instructions.

Conditional language, such as, among others, “can,” “could,” “might,” or“may,” unless specifically stated otherwise, or otherwise understoodwithin the context as used, is generally intended to convey that certainimplementations could include, while other implementations do notinclude, certain features, elements, and/or operations. Thus, suchconditional language is not generally intended to imply that features,elements, and/or operations are in any way required for one or moreimplementations or that one or more implementations necessarily includelogic for deciding, with or without user input or prompting, whetherthese features, elements, and/or operations are included or are to beperformed in any particular implementation.

Many modifications and other implementations of the disclosure set forthherein will be apparent having the benefit of the teachings presented inthe foregoing descriptions and the associated drawings. Therefore, it isto be understood that the disclosure is not to be limited to thespecific implementations disclosed and that modifications and otherimplementations are intended to be included within the scope of theappended claims. Although specific terms are employed herein, they areused in a generic and descriptive sense only and not for purposes oflimitation.

What is claimed is:
 1. A device for communicating enhanced directionalmulti-gigabit (EDMG) frames, the device comprising: at least one memorythat stores computer-executable instructions; and at least one processorconfigured to access the at least one memory, wherein the at least oneprocessor is configured to execute the computer-executable instructionsto: perform iterations using a first Golay sequence and a second Golaysequence, wherein a first iteration of the iterations comprisesmultiplying the first Golay sequence by a vector and adding that to thesecond Golay sequence; generate a first orthogonal frequency-divisionmultiplexing (OFDM) symbol based on the iterations; generate an EDMGframe, the EDMG frame including a channel estimation field (CEF)comprising the first OFDM symbol; and cause to send the EDMG frame usinga number of spatial streams.
 2. The device of claim 1, wherein the CEFfurther comprises a second OFDM symbol.
 3. The device of claim 1,wherein a second iteration of the iterations comprises multiplying athird Golay sequence by the vector and adding that to a fourth Golaysequence.
 4. The device of claim 1, wherein the vector is based on thenumber of spatial streams.
 5. The device of claim 1, wherein a length ofthe first OFDM symbol is
 176. 6. The device of claim 1, wherein thenumber of spatial streams is four.
 7. The device of claim 1, furthercomprising a transceiver configured to transmit and receive wirelesssignals comprising the EDMG frame.
 8. The device of claim 7, furthercomprising one or more antennas coupled to the transceiver.
 9. Anon-transitory computer-readable medium storing computer-executableinstructions which when executed by one or more processors result inperforming operations comprising: performing iterations using a firstGolay sequence and a second Golay sequence, wherein a first iteration ofthe iterations comprises multiplying the first Golay sequence by avector and adding that to the second Golay sequence; generating a firstorthogonal frequency-division multiplexing (OFDM) symbol based on theiterations; generating an EDMG frame, the EDMG frame including a channelestimation field (CEF) comprising the first OFDM symbol; and causing tosend the EDMG frame using a number of spatial streams.
 10. Thenon-transitory computer-readable medium of claim 9, wherein the CEFfurther comprises a second OFDM symbol.
 11. The non-transitorycomputer-readable medium of claim 9, wherein a second iteration of theiterations comprises multiplying a third Golay sequence by the vectorand adding that to a fourth Golay sequence.
 12. The non-transitorycomputer-readable medium of claim 9, wherein the vector is based on thenumber of spatial streams.
 13. The non-transitory computer-readablemedium of claim 9, wherein a length of the first OFDM symbol is
 176. 14.The non-transitory computer-readable medium of claim 9, wherein thenumber of spatial streams is four.
 15. A method, comprising: performing,by at least one processor of a device iterations using a first Golaysequence and a second Golay sequence, wherein a first iteration of theiterations comprises multiplying the first Golay sequence by a vectorand adding that to the second Golay sequence; generating, by the atleast one processor, a first orthogonal frequency-division multiplexing(OFDM) symbol based on the iterations; generating, by the at least oneprocessor, an EDMG frame, the EDMG frame including a channel estimationfield (CEF) comprising the first OFDM symbol; and causing to send, bythe at least one processor, the EDMG frame using a number of spatialstreams.
 16. The method of claim 15, wherein the CEF further comprises asecond OFDM symbol.
 17. The method of claim 15, wherein a seconditeration of the iterations comprises multiplying a third Golay sequenceby the vector and adding that to a fourth Golay sequence.
 18. The methodof claim 15, wherein the vector is based on the number of spatialstreams.
 19. The method of claim 15, wherein a length of the first OFDMsymbol is
 176. 20. The method of claim 15, wherein the number of spatialstreams is four.